Positive displacement pump with dual coacting flexible vane-type impellers



Sept. 27, 1955 C. KNUTH POSITIVE DISPLACEMENT PUMP WITH DUALCOACTINGFLEXIBLE VANE-TYPE IMPELLERS Fi led De 2 Sheets-She t 1 INVENTOR.

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POSITIVE DISPLACEMENT PUMP WITH DUALCOACTING FLEXIBLE VANE-TYPEIMPELLERS F5166. D60. 20, 1952 2 Sheets-Sheet 2 I IN V EN TOR.

United States Patent POSITIVE DISPLACEMENT PUMP WITH DUAL COACTINGFLEXIBLE VANE-TYPE IlVIPELLERS Carl Knuth, Fond .du Lac, Wis., assiguorto Kiekhaefer Corporation, Cedarburg, Wis., a company of WisconsinApplication December 20, 1952, Serial No..327,079

3 Claims. (Cl. 230141) This invention relates to flexible vane-type,positive displacement blowers or pumps.

Theinvention provides a pump or blower which includes two impellersoppositely rotated in synchronization and having corresponding flexiblevanes which approach and successively engage and depress each other in agenerally medial plane respecting the rotational axes of the impellers.

An object of the invention is to provide more eflicient pump operationof flexible vane-type impellers.

Another object is to allow operation of flexible vanetype impellers athigher speeds to adapt the pump to various types of service such asair-blowers and superchargers for engines.

Another object is to reduce the frictional wear of the vanes of theimpellers.

Another object is to increase the capacity of the blower or pump.

Another object is to increase the normal useful life of flexiblevane-type pump impellers particularly for operation at high speeds.

These and other objects and advantages will be more fully set forth inthe following description of the invention as illustrated in theaccompanying drawings.

In the drawings:

Figure 1 is a transverse section showing the pump impellers in elevationas disposed within the pump housing; and

Fig. 2 is a longitudinal section through the pump housing on the axis ofthe impeller shafts showing the intermeshing gears which maintain theshafts and impellers in synchronization.

The pump 1, shown in the drawings, includes the parallel shafts 2 and 3which carry the duplicate impellers 4 and 5, respectively. The housing 6comprises the separable members 7 and 8 which are joined to form theimpeller chamber 9 and enclose impellers 4 and therein. The bearings 10journally support shafts 2 and 3 and are carried by members 7 and 8 onopposite sides of the respective impellers. The corresponding ends ofshafts 2 and 3 carry the meshing gears 11 and 12 respectively andoutside of housing 6.

The driving coupling member 14 is secured to shaft 3 adjacent to gear 12and provides for operation of the pump by suitable drive means, notshown.

In the operation of pump 1, shafts 2 and 3 are driven in oppositedirections to rotate impellers 4 and 5 at corresponding speeds and inopposite directions.

Each impeller includes a hub 15 and the tapered radially extending vanes16 which are equally spaced about hub 15 and are of equal length. Eachvane 16 is of flexible material and suitable construction which allowsthe vane to be deflected radially toward the axis of rotation. Theimpellers 4 and 5, shown in the drawings, illustrate a preferredconstruction wherein the hub 15 and vanes 16 are integrally formed ofmolded synthetic rubber and each hub 15 is bonded over the metal bushing17 which is mounted directly on the respective shaft and rotationallysecured thereto by the key 18. With the opposite rotation of the shafts,the respective vanes 16 are disposed in corresponding relation toapproach and pass together between the shafts.

According to the invention, the diameter of each of impellers 4 and 5 issubstantially greater than the distance between the axes of shafts 2 and3 whereby the vanes approaching each other with rotation of the shaftsprovided for as described, are adapted to engage and deflect each otherto effect a delivery of fluid by displacement of the volume of fluidtherebetween.

The inner dimensions of chamber 9 comprise cylindrical sections whichcorrespond generally to the combined dimensions of impellers 4 and 5 andwhich sections intersect to define a plane medial to the axes of shafts2 and 3. The inlet and outlet connections 19 and 20 respectively, to andfrom chamber 9 are disposed generally in the plane referred to and onopposite sides of chamber 9. The dimensions of chamber 9 provide onlythe necessary operating clearances for impellers 4 and 5 to allow theimpellers to be rotated with limited friction and leakage between thesame and the walls of chamber 9.

The fluid entering chamber 9 through inlet 19 is carried around theoutside of the chamber between the adjacent vanes 16 of each impeller tothe outlet 20 where the approaching corresponding vanes engage at theirouter extremities. With further rotation, the same vanes are deflectedby their further face-to-face engagement to pass between shafts 2 and 3and to effect the partial displacement of the fluid therebetween in thedirection of outlet 20. During such engagement the following, orsucceeding corresponding vanes more adjacent to outlet 20 engagesufliciently in advance of the release of the adjacent forward vanes toprevent intermediate loss of pressure of the fluid.

The displaced fluid is forced in the direction of outlet 20 underpressure. The vanes 16 of each impeller are radially spaced so that thesubsequent engagement of corresponding vanes of each impeller occurswhile such pressure is maintained to reduce pulsation. The fluidcontinues to be displaced by the engaging vanes to cushion theengagement of the next succeeding vanes and to prevent their eventualbreakdown from their tipto-tip engagement at high speeds.

The undisplaced fluid is released in the direction of inlet 19 with themutual disengagement of the vanes for recirculation with furtherrotation of shafts 2 and 3. Inlet 19 is located with respect to thereleased vanes 16 so that the velocity of the fluid entering chambertends to retard the vanes and reduces the tendency of the vanes to whipas the same are successively released at high speeds. At such highspeeds the fluid carried between vanes 16 and discharged in thedirection of outlet 20 limits the impact of the vanes following asdescribed whereby higher operating speeds are permitted Withoutbreakdown of the vanes by the impacts thereof.

The invention utilizes flexible vane-type impellers which do not requiremachining to close tolerances for the necessary seal particularly inhandling air or gases and adapts such vane-type impellers to higheroperating speeds and corresponding greater deliveries.

The pump is intended for handling large quantities of gases atrelatively low pressures and particularly as an engine supercharger.

Various embodiments of the invention may be employed within the scope ofthe accompanying claims.

I claim:

1. A positive displacement pump comprising two parallel shafts,intermeshing gears carried by and fixed on said shaft to synchronizetheir rotation in opposite directions, one of said shafts being adaptedto be driven and to drive the other thereof through said gears, ahousing including walls each extending normal to the axes of said shaftsand having journal bearing means supporting said shafts, said housinghaving an outer body forming a chamber between said walls, a flexiblevanetype impeller having a diameter greater than the distance betweenthe axes of said shafts and mounted on each of said shafts and withinsaid chamber, the outer dimensions of said chamber corresponding to thecombined outer dimensions of said impellers and providing limitedoperating clearance therefor whereby adjacent vanes of each impeller areadapted to entrain a fixed volume of fluid therebetween, said impellersbeing fixed relative to said shafts to rotate therewith in oppositedirections without inter-meshing and having corresponding vanes disposedto engage at their tips upon approaching each other with oppositerotation, said housing having an outlet opening from said chamberadjacent to said approaching vanes, said vanes upon engagement at theirtips and with further opposite rotation being flexible to bend on eachother generally in a plane extending medially of said shafts todischarge the entrained fluid, said housing having an inlet opening forthe admission of the fluid to the chamber at the point of mutual releaseof the corresponding vanes after movement thereof from between saidshafts.

2. The invention as defined in claim 1 wherein the discharge of fluid bythe engagement of corresponding vanes is effected in the direction ofthe outlet and between the following corresponding vanes approachingeach other to reduce the impact of their engagement.

3. The invention as defined in claim 1 wherein the inlet is located sothat the fluid entering the chamber is effective to be directed againstthe vanes passing between the shafts and to cushion the release of saidvanes.

References Cited in the file of this patent UNITED STATES PATENTS 26,962Adams Jan. 31, 1860 263,196 Morse Aug. 22, 1882 2,403,796 Hanna July 9,1946 2,407,753 Wallgren Sept. 17, 1946 2,451,603 Barker Oct. 19, 19482,467,524 Fernstrum Apr. 19, 1949 2,567,699 Devlin Sept. 11, 19512,572,334 Guibert Oct. 23, 1951

